title: Prostaglandin E1 or E2 (PGE1, PGE2) prevents premature luteolysis induced by progesterone given early in the estrous cycle in ewes.
abstract: The objective of this study was to determine whether prostaglandin E1 (PGE1) or prostaglandin E2 (PGE2) prevents premature luteolysis in ewes when progesterone is given during the first 6 days of the estrous cycle. Progesterone (3 mg in oil, im) given twice daily from Days 1 to 6 (estrus = Day 0) in ewes decreased (P < 0.05) luteal weights on Day 10 postestrus. Plasma progesterone concentrations differed (P < 0.05) among the treatment groups; toward the end of the experimental period, concentrations in jugular venous blood decreased (P < 0.05) compared with the other treatment groups. Plasma progesterone concentrations in ewes receiving PGE1 or PGE1 + progesterone were greater (P < 0.05) than in vehicle controls or in ewes receiving PGE2 or PGE2 or PGE2 + progesterone. Chronic intrauterine treatment with PGE1 or PGE2 prevented (P < 0.05) decreases in plasma progesterone concentrations, luteal weights, and the proportion of luteal unoccupied and occupied LH receptors on Day 10 postestrus in ewes given exogenous progesterone, but did not affect (P > 0.05) concentrations of PGF2α in inferior vena cava blood. Progesterone given on Days 1 to 6 in ewes advanced (P < 0.05) increases in PGF2α in inferior vena cava blood. We concluded that PGE1 or PGE2 prevented progesterone-induced premature luteolysis by suppressing loss of luteal LH receptors (both unoccupied and occupied).
authors.affiliation: Department of Human Nutrition, Food, and Animal Sciences, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Yoshie S
authors.initials: YS
authors.lastname: Weems
authors.forename: Aaron
authors.initials: A
authors.lastname: Raney
authors.forename: John
authors.initials: J
authors.lastname: Pang
authors.forename: Tracie
authors.initials: T
authors.lastname: Uchima
authors.forename: Esther
authors.initials: E
authors.lastname: Lennon
authors.forename: Drew
authors.initials: D
authors.lastname: Johnson
authors.forename: Torrence M
authors.initials: TM
authors.lastname: Nett
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Randel
authors.forename: Charles W
authors.initials: CW
authors.lastname: Weems
mesh_terms: D000527:Alprostadil / Q000494:pharmacology*; D000818:Animals; D015232:Dinoprostone / Q000494:pharmacology*; D030762:Estrous Cycle; D003341:Luteolysis / Q000187:drug effects*; D011374:Progesterone / Q000097:blood / Q000494:pharmacology*; D012756:Sheep / Q000502:physiology*
chemical_list: D011374:Progesterone; D000527:Alprostadil; D015232:Dinoprostone
keywords: Corpus luteum; Endocrinology (female); Maternal recognition of pregnancy; Sheep